What is the recurrence risk for severe myopia with an affected sibling?

The recurrence risk for severe myopia in a family with an affected sibling is estimated to be around 5%. This risk reflects the genetic and environmental contributions associated with myopia. Familial aggregation of myopia suggests a heritable component, and studies have shown that the presence of one affected sibling increases the likelihood of another sibling also being affected, although the exact recurrence risks can vary based on additional factors such as parental myopia status.

Severe myopia tends to follow a complex inheritance pattern, meaning it is affected by multiple genes along with potential environmental influences. In general, the recurrence risks for conditions like severe myopia are often calculated based on population studies and observed familial patterns, leading to the estimate of about 5% for a sibling of an affected individual.

While 10% and 15% might seem plausible, they are generally considered to be higher than what is supported by the current understanding of the inheritance patterns for severe myopia. The risk of 2% is too low to accurately reflect the marked increase in likelihood conferred by having an affected sibling. Thus, based on genetic epidemiological studies, a 5% risk is the most accepted figure.